7027 Thornbury Castle

In GWR terms they are renewals, which by and large meant a good as new locomotive using such second hand parts as were suitable for reuse. There are a number of such built by the GWR that survive in preservation, GWR built Manors, the 72s, the Dukedog. Beyond that it's known that some other new GWR locomotives were turned out from the works with some second hand parts, boilers and tenders being documented, and in the course of normal overhauls every locomotive received parts previously installed on others. So the distinction you are claiming is in historical terms largely meaningless. Renewals weren't additions to the fleet, instead they were replacements of earlier locomotives. The majority of locomotives built by the GWR were classed as renewals, including, I believe, all built under Collett and Hawksworth.

 

If 4709 gets finished, with whichever boiler, surely it will look very close to right, the main (allegedly unavoidable) difference from the originals being a slight reduction in height. (Also slightly slimmer cylinders?) Reducing the height of the top of the boiler and keeping the right chimney will be less noticeable than fitting a shorter chimney.

 

My biggest problem with this is that, taking both engines at face value, which is the further advanced engine in terms of construction/ restoration, the castle could be a rolling chassis quite quickly, and has already had a lot of work done, the 47, I don't think is even any were near a rolling chassis, possibly with remedial work being needed to check for possible issues with past work done.
Then there is the story of the progressive modification of the castle locomotives during their life, an early castle is very different to the later builds, 7027, is as far as i know not an engine represented in the GWS collection, with the 3-row superheater, and as such, you have to question their own aims, I'm not against building an 47xx but don't think that 7027, is the right engine to be used as a donor, there is a compromise, that could be done, if a spare boiler of an broken up 28, was used to recreate the first 47xx as it first appeared, and the correct pattern of boiler, could be manufactured and funds to do it, raised over the ten year ticket,

 

The problem that I see is that an existing locomotive has been scrapped solely to provide parts for a locomotive that does not currently, and as I see it will never actually exist, the best that it will be is a pastiche, is it not 'Bad' enough that the cylinders of a 28 that has been scrapped for this purpose have been altered beyond use even as spares before being rejected as unsuitable? This is neither the actions of preservationists, restorers nor enthusiasts but that of the misguided.

 

I don't think that there is any intention to reduce the height of the boiler. A Castle has larger wheels, so I would presume that the frames are deeper than a 47xx. Therefore the brackets on which a Castle's boiler slides on the frames are higher up, compared with a 47xx. Therefore if they use 7027's boiler, those brackets will have to mounted lower down; this has nothing to do with lowering the boiler.

 

Again I ask, why would you want to reduce the height of the loco? It isn't going to work on the main line and certainly not under the wires. For shunting out of the GWS depot at Didcot just ensure that the high points (chimney, safety valve bonnet, cab roof) are easily detached.

Oh, you've read on Nat Pres that it is going to be a main line engine? Well, what can I say? Some folk need to get real.

Peter

 

They manage to get 2999 in and out with minimal faffing out and I assume that's 'standard' GWR height?

What they don't want to do is get into the fuss they had with 6023 where they lowered it, buggered up the draughting spent a few years trying to sort it and then seem to have returned her to standard?

 

You've forgotten conversion from double to single chimney.

 

Not really, whilst fitting the double chimneys undoubtedly improved them from 1955 onwards, I don't recall any suggestion that they steamed badly and ate coal for breakfast in original single chimney form.

 

Think the fundamental question with the 47xx is one of expectation to work on the Big railway, If there is no expectation then the No1 boiler would suffice, despite the fact that there were almost as many ' it wont be a proper 47xx' knockers for that as there are for this

 

That's not the point. They wouldn't necessarily have had the correct blast pipe for a single chimney; the latter was also altered from original.

 

What they have told me is that it's not going on the main line but it will have to get in and out of Didcot and for that reason the height has to be reduced from that of the original 4700s. I merely pass that statement on: I take no responsibility for it. I don't know whether temporary removal of the chimney and the safety valve bonnet from the correct No.7 boiler would be enough, or if not why not..

 

I am indeed sir.

 

I do find that hard to believe. According to Wikipedia, a 47xx is 1/4" higher than a Castle. 5043 and 7029 seem to run under the wires frequently, seemingly without any height reduction. I have travelled on the footplate of 5051 under the wires, again without modification. Are the wires lower at Didcot than anywhere else?

For example, at a Thatcham level crossing, the road clearance is 5m (16ft 4in), nearly 3ft more than a 47xx!

https://www.newburytoday.co.uk/news/height-restriction-for-thatcham-level-crossing-9183297/

 

What a splendid informative post, l am very grateful. You learn something every day. I responded to this thread in the beginning not just to challenge an opinion but to learn and modify my own.

 

5043 and 7029 have been lowered by 2.5 inches as all locos have to be 13ft 1 inch or below to run on Netwoprk Rail.

 

I think they planned to lower 4079 as well until the GWS decided to can mainline running.

 

It would be interesting to know how that was done. Comparing old and new photographs, the chimney of 7029 doesn't seem to be noticeably lower.

 

1.25” off tyre profile would do it without any other modification - quite expensive in wasted tyre wear, but doable. (No idea if that was done in that case, just suggesting how it could be done).

Ignore me, I can’t count.

Tom

 

The castle double chimneys and safety valves always were below 13 ft 1 in, the cab roof has been lowered by 2 1/2" on 7029 and 5043, also 5029. I believe 7029 and 5029 were fitted with new tyres at last overhaul and no reduction in thickness was required. 5029 had the capuchon cut off the top of the chimney to get it down to 13 ft 1 in.